Bone broth supplies several amino acids involved in hair structure, but no clinical trial has tested whether drinking bone broth itself promotes hair growth. The research that does exist on collagen and hair involves purified collagen peptide supplements, not simmered bones. And even those supplement studies are mostly limited to lab dishes and mice. So while bone broth is a reasonable source of protein and minerals, calling it a hair-growth remedy stretches well beyond what the science supports.
What Bone Broth Actually Contains
The appeal of bone broth for hair comes down to collagen. When you simmer animal bones for hours, collagen from connective tissue breaks down into gelatin and releases amino acids into the liquid. Analysis of bovine bone broths has identified seventeen amino acids, with glycine, alanine, proline, aspartic acid, and glutamic acid showing up in the highest concentrations.1Food Chemistry: X. Operational parameters and key characteristics of amino acids and flavor compounds profiles of bovine bone clear and white broths Those five amino acids happen to be the building blocks of collagen, which makes up a significant portion of the dermal layer surrounding hair follicles.
Chicken-based bone broths also contain glycosaminoglycans like hyaluronan and chondroitin sulfate, compounds that help maintain tissue hydration and structure.2PubMed. Hyaluronan and chondroitin sulfate in chicken-vegetable bone broth delay osteoporosis progression These compounds are better studied for joint and bone health than for hair, but they do play a role in the extracellular matrix that surrounds every hair follicle. On paper, the ingredient list looks promising. The problem is the amounts.
Bone Broth Versus Collagen Supplements
A controlled comparison of bone broth and collagen supplements found that broth prepared from a standardized recipe delivered significantly lower concentrations of the key collagen-related amino acids: hydroxyproline, glycine, proline, hydroxylysine, leucine, and lysine were all well below the levels in a 20-gram dose of a collagen supplement.3International Journal of Sport Nutrition and Exercise Metabolism. Bone Broth Unlikely to Provide Reliable Concentrations of Collagen Precursors Compared With Supplemental Sources of Collagen Used in Collagen Research That same study found huge variability between batches, especially in broths prepared without a strict recipe. Café-prepared varieties scored highest in amino acid content, while commercial off-the-shelf broths scored lowest.
This variability is a real headache for anyone hoping to use bone broth therapeutically. You might drink a mug of homemade broth one day that has a decent amino acid profile, then open a carton of store-bought broth the next day and get a fraction of those nutrients. The researchers concluded that if collagen precursors are shown to help with new collagen synthesis, bone broth is unlikely to serve as a consistently reliable source of those precursors.3International Journal of Sport Nutrition and Exercise Metabolism. Bone Broth Unlikely to Provide Reliable Concentrations of Collagen Precursors Compared With Supplemental Sources of Collagen Used in Collagen Research Supplements, by contrast, are manufactured to deliver a known dose every time.
What Collagen Peptides Do to Hair Follicle Cells
Even though the bone broth evidence is thin, there is a growing body of research on purified collagen peptides and hair. Most of it comes from cell culture and animal studies rather than human trials, but the findings are worth understanding because they explain why collagen keeps appearing in hair-care marketing.
Fish-derived collagen peptides stimulated the growth of human dermal papilla cells, the specialized cells at the base of each hair follicle that regulate the hair growth cycle. In mice, oral collagen peptide treatment over six weeks increased hair regrowth and boosted several growth factors while reducing a growth-inhibitory signal. The treated mice showed thicker hair follicles and a higher ratio of active-to-resting follicles.4PubMed Central. Hair-Growth-Promoting Effects of the Fish Collagen Peptide in Human Dermal Papilla Cells and C57BL/6 Mice Modulating Wnt/β-Catenin and BMP Signaling Pathways A separate study using low-molecular-weight collagen peptides found a similar pattern: the peptides promoted dermal papilla cell proliferation and spurred the formation of entirely new hair follicles in a dose-dependent way.5PubMed Central. Low Molecular Weight Collagen Peptide (LMWCP) Promotes Hair Growth by Activating the Wnt/GSK-3β/β-Catenin Signaling Pathway
Another collagen peptide product accelerated the transition from the resting phase of hair growth to the active phase in mice and promoted hair follicle elongation in human follicle tissue grown outside the body.6PubMed. AP collagen peptides (APCPs) promote hair growth by activating the GSK-3β/β-catenin pathway and improve hair condition All three of these studies point to the same signaling pathway being activated, which lends some coherence to the overall finding. But the peptides used in these experiments were highly purified, standardized products at known doses, not the variable soup you get from simmering a chicken carcass.
Can Your Body Even Use the Collagen You Swallow?
A common objection to any oral collagen product is that your digestive system breaks proteins into individual amino acids, so the collagen you drink just becomes generic protein. This is partially true but not the whole story. A randomized crossover study in healthy adults showed that after ingesting collagen hydrolysate, plasma levels of hydroxyproline (a collagen-specific amino acid) reached concentrations six to ten times higher than baseline within about two hours. Roughly 36 to 47 percent of the hydroxyproline circulating in blood remained bound in small peptide chains rather than existing as free amino acids.7PubMed Central. Absorption of bioactive peptides following collagen hydrolysate intake: a randomized, double-blind crossover study in healthy individuals Those peptide fragments may act as signaling molecules that influence how your cells behave, not just as raw building materials.
The catch is that this absorption study used purified collagen hydrolysate, not bone broth. Hydrolysate is collagen that has been enzymatically broken into small peptides specifically designed for absorption. Bone broth delivers collagen mainly as larger gelatin molecules, which require more digestion and likely produce a less predictable mix of peptide fragments. So even if the absorption pathway works, bone broth may not feed into it efficiently.
The One Human Hair Trial Worth Knowing About
Direct human clinical evidence connecting collagen to hair growth is scarce. One randomized, double-blind, placebo-controlled trial tested a marine-based supplement complex containing a proprietary blend of shark cartilage-derived compounds along with vitamins and minerals in men with thinning hair. After six months, the supplement group showed significant increases in total hair count, hair density, and terminal hair density compared to placebo, and the hair-pull test showed less shedding.8PubMed. A 6-month, randomized, double-blind, placebo-controlled study evaluating the ability of a marine complex supplement to promote hair growth in men with thinning hair
This is encouraging, but it comes with a big asterisk: the supplement was a multi-ingredient formulation, not pure collagen. Teasing apart which component drove the results is impossible from a single trial. And a separate multicenter study found that a combination product containing hydrolyzed collagen plus vitamins and minerals improved the ratio of actively growing to resting hairs and increased hair density over 16 weeks, but again, collagen was one ingredient among several.9PubMed Central. Targeted Nutritional Supplementation for Telogen Effluvium: Multicenter Study on Efficacy of a Hydrolyzed Collagen, Vitamin-, and Mineral-Based Induction and Maintenance Treatment We still lack a clean trial of collagen alone for hair growth in humans, let alone a trial of bone broth.
Glycine, Proline, and Why Individual Amino Acids Matter
Hair is mostly keratin, not collagen, so the amino acids in bone broth do not get incorporated directly into hair strands. Instead, their potential value lies in supporting the tissue environment around each follicle. Glycine, the most abundant amino acid in bone broth, has documented anti-inflammatory properties. It can dampen the activity of inflammatory signaling pathways in multiple cell types.10PubMed Central. Glycine: The Smallest Anti-Inflammatory Micronutrient Chronic inflammation around the hair follicle is implicated in some types of hair loss, so an anti-inflammatory amino acid could theoretically help maintain a healthier scalp environment.
Proline and glycine together also contribute to the mechanical properties of hair-like fibers. Research on bioinspired fusion peptides found that a balanced proportion of proline and glycine improved the flexibility and elasticity of protein fibers, characteristics that relate to hair breakage resistance rather than growth per se.11Cell Reports Physical Science. Bioinspired fusion peptides for hair recovery and thermal protection Preventing breakage matters for the appearance of hair fullness even if it does not change how fast follicles produce new strands.
None of this means you need bone broth specifically to get glycine or proline. Both are non-essential amino acids your body can synthesize on its own, and they are abundant in any protein-rich diet. For someone eating adequate protein, adding bone broth is unlikely to meaningfully boost the supply of these amino acids to the scalp.
When Nutrition Actually Does Affect Hair
The most straightforward connection between diet and hair growth involves correcting genuine deficiencies. Iron, zinc, biotin, vitamin D, and protein deficiency can all contribute to hair shedding. A review of the evidence found that for patients with documented nutritional deficiencies, correcting those deficiencies can improve hair growth. However, the same review emphasized that supplementing these nutrients in the absence of a documented deficiency has not been shown to help, and some supplements carry a risk of worsening hair loss or causing toxicity at high doses.12PubMed Central. Diet and hair loss: effects of nutrient deficiency and supplement use
Bone broth does supply some of these nutrients. It contains modest amounts of zinc, iron, and other minerals depending on the bones used and how long they are simmered. But it is not a concentrated source of any single micronutrient in the way that, say, red meat is for iron or oysters are for zinc. If you have a genuine deficiency affecting your hair, bone broth alone probably won’t fix it. If you don’t have a deficiency, extra nutrients from bone broth won’t push hair growth beyond its normal rate.
The Lead Question
One concern that comes up whenever bone broth is discussed for health is heavy metal contamination. Bones accumulate lead over an animal’s lifetime, and simmering them can leach that lead into the liquid. A small controlled study of organic chicken broth found lead levels of roughly 7 to 9.5 micrograms per liter, compared to 0.89 micrograms per liter in the tap water used as a control.13PubMed. The risk of lead contamination in bone broth diets That sounds alarming, but context matters.
A broader analysis of commercial bone broths found that the doses of toxic metals per serving, including lead, cadmium, and aluminum, were well below established safety thresholds. The hazard quotients were generally less than 0.002, meaning the risk from a single serving is regarded as minimal.14PubMed Central. Essential and toxic metals in animal bone broths For occasional consumption, bone broth does not appear to pose a meaningful heavy metal risk. But if you are drinking multiple cups daily as a health regimen, the cumulative exposure is worth keeping in mind, especially during pregnancy or in young children who are more sensitive to lead.
Plant-Based Collagen Alternatives
For people who avoid animal products, a newer generation of vegan collagen-like supplements has entered the market. These are typically recombinant proteins produced by genetically engineered yeast or bacteria, designed to mimic the amino acid profile of animal collagen. One clinical study tested a vegan collagen product at three dose levels and reported a significant improvement in hair growth rate ranging from about 39 to 50 percent over 60 days, along with increases in hair density and thickness at the highest dose.15PubMed. Revitalizing skin, hair, nails, and muscles: Unlocking beauty and wellness with vegan collagen
Those are striking numbers, though the study is a single trial and the results would need replication before drawing firm conclusions. What it does suggest is that the specific amino acid composition matters more than the animal origin. If a plant-based product delivers the right peptides in sufficient amounts, it may work similarly to animal-derived collagen. This further weakens the case for bone broth specifically, since even within the collagen world, the precise product formulation appears to matter more than the source animal.
Why the Hype Outpaces the Evidence
Bone broth occupies an odd position in the wellness landscape. It has genuine nutritional value as a source of protein, minerals, and gelatin. It has a long cultural history in cuisines around the world as a comforting, nourishing food. And the collagen research, while early-stage, does suggest that collagen-derived peptides could influence hair follicle biology. The problem is that these three facts get blended together in marketing and social media into a conclusion that does not follow: that drinking bone broth will grow your hair.
Each link in the chain is weak. Bone broth delivers collagen-related amino acids, but in unpredictable and generally low amounts compared to supplements. Collagen peptides show promise for hair in lab and animal models, but those studies use purified, precisely dosed products. The handful of human trials that showed positive results tested multi-ingredient supplements, not bone broth or even collagen alone. And the absorption research, while it demonstrates that collagen peptides do survive digestion in bioactive forms, was conducted with hydrolysate, not gelatin-heavy broth.
If you enjoy bone broth, it can be a perfectly healthy part of your diet. It provides hydration, electrolytes, and protein with relatively few calories. But treating it as a hair growth intervention means bypassing cheaper, more effective options. Someone genuinely concerned about hair loss would be better served by getting bloodwork to check for nutritional deficiencies, considering evidence-based treatments appropriate for their type of hair loss, and, if they want to explore the collagen angle, using a standardized collagen peptide supplement with a known dose rather than hoping their broth happens to contain enough of the right amino acids.
How Cooking Methods Change the Equation
If you do decide to drink bone broth for general health and are curious whether preparation matters, the research is clear that it does. Longer simmering times extract more collagen, and the type of bone matters. Joints and knuckle bones are richer in cartilage and collagen than marrow bones. Adding an acid like vinegar to the water can help break down bone matrix and release more minerals and amino acids, though the effect is modest. Café-prepared broths, which tend to use more bones relative to water and simmer for longer, consistently showed the highest amino acid content in the comparison study mentioned earlier.3International Journal of Sport Nutrition and Exercise Metabolism. Bone Broth Unlikely to Provide Reliable Concentrations of Collagen Precursors Compared With Supplemental Sources of Collagen Used in Collagen Research
Pressure cooking has also gained attention for its ability to break down collagen faster than conventional simmering. A shorter cook under high pressure can yield a broth that gels firmly when refrigerated, a visual indicator of gelatin content. Whether that translates to a meaningfully higher dose of bioactive peptides after digestion remains an open question. But if you are going to make bone broth and want the most collagen-relevant product, a thick, gelatinous broth made from joint-heavy bones is the version worth aiming for rather than a watery stock made primarily from marrow bones.