Collagen peptides are not proven unsafe during pregnancy, but there also isn’t enough research to confirm they’re safe. No major health authority has issued a clear yes or no on supplemental collagen during pregnancy, which leaves many expecting parents in a frustrating gray zone. Here’s what the available evidence actually tells us so you can make an informed choice.
Why There’s No Clear Answer Yet
Collagen peptides fall into the category of dietary supplements, which means they aren’t evaluated or approved by the FDA before hitting store shelves. Unlike prenatal vitamins, which have decades of safety data behind them, collagen supplements simply haven’t been studied in pregnant populations. WebMD’s clinical summary puts it bluntly: there isn’t enough reliable information to know if collagen peptides are safe during pregnancy or breastfeeding.
That doesn’t mean collagen is harmful. It means no one has run the controlled trials needed to say with confidence that it’s fine. For context, the typical dosage range studied in non-pregnant adults is 2.5 to 10 grams daily for up to six months. Whether those doses carry any additional risk during pregnancy remains unanswered.
What Collagen Actually Provides
Collagen peptides are broken-down fragments of collagen protein, sourced from cow hides (bovine), fish skin and scales (marine), or pig tissue (porcine). When you digest them, they break down further into amino acids, primarily glycine, proline, and hydroxyproline. These aren’t exotic compounds. They’re amino acids your body already uses and can obtain from whole foods like bone broth, chicken, fish, and eggs.
Proline plays a genuinely important role in pregnancy. It fuels protein synthesis, supports the production of polyamines (molecules that regulate cell growth and DNA synthesis), and contributes to placental development. Animal research has shown that higher proline availability increases the surface area of the placenta’s nutrient-exchange zone, improving oxygen and nutrient delivery to the embryo. Proline also supports the synthesis of arginine, another amino acid critical for vascular development in the placenta.
But here’s the key distinction: needing these amino acids during pregnancy doesn’t mean you need to get them from a collagen supplement. A diet that meets your overall protein needs will supply glycine and proline through regular food sources.
Protein Needs During Pregnancy
During the second and third trimesters, the recommended daily protein intake rises to about 1.1 grams per kilogram of body weight, calculated from your pre-pregnancy weight. For someone who weighed 150 pounds (68 kg) before pregnancy, that works out to roughly 75 grams of protein per day. Women carrying multiples need even more, about 50 extra grams daily on top of the standard non-pregnant recommendation.
Collagen peptides can contribute to your total protein count, but they’re an incomplete protein. They’re missing or low in several essential amino acids, particularly tryptophan. So while a scoop of collagen powder might add 10 grams of protein to your morning smoothie, it can’t replace balanced protein sources like poultry, fish, legumes, dairy, or eggs that deliver the full amino acid profile your body and your baby need.
The Heavy Metal Concern
One concrete risk worth understanding is contamination. Because collagen is derived from animal tissues that accumulate environmental toxins over time, supplements can contain trace amounts of heavy metals like lead, arsenic, cadmium, and mercury. This matters more during pregnancy, when even low-level lead exposure can affect fetal development.
A 2025 analysis of marine collagen supplements found that arsenic was the most common contaminant, averaging 0.59 mg/kg, followed by lead at 0.13 mg/kg. Mercury appeared in only 12% of samples and at very low levels. None of the products tested exceeded European Union safety limits, and the estimated daily intake from a standard dose fell far below established safety thresholds. Notably, collagen derived from jellyfish and mackerel skin showed no detectable toxic metals at all.
The reassuring takeaway is that reputable products at recommended doses appear to fall well within safe exposure limits for the general population. The less reassuring part is that pregnancy lowers the threshold for concern, supplements aren’t consistently tested for contaminants in the U.S., and cheaper or unregulated brands may not meet the same standards. If you do choose to use collagen, selecting a product that carries a third-party testing seal (like NSF, USP, or ConsumerLab) reduces this risk considerably.
Will Collagen Prevent Stretch Marks?
This is one of the most common reasons pregnant people consider collagen, and the evidence is disappointing. Stretch marks form when rapid skin expansion during pregnancy causes collagen fibers in the deeper layers of skin to slide apart and separate irreversibly. Hormones like estrogen and relaxin accelerate this process by changing the structure of the tissue between collagen fibers.
A Cochrane review examining topical creams with active ingredients, including one product containing collagen-elastin hydrolysates, found no statistically significant difference in stretch mark development compared to placebo or no treatment. Across five trials involving 474 women, the creams didn’t reliably prevent stretch marks, and they didn’t reduce their severity either. If topical collagen applied directly to the skin doesn’t prevent stretch marks, there’s little reason to expect that swallowed collagen peptides would perform better.
Choosing a Safer Approach
If you’re set on taking collagen peptides during pregnancy, a few practical steps can reduce potential risks. First, check the source. Bovine and marine are the most common, and you should avoid any source you have an allergy to, whether that’s fish, beef, or pork. Marine collagen from certain species like jellyfish and mackerel has shown cleaner contamination profiles in testing.
Second, look for third-party verification. Supplements tested by independent labs are more likely to have accurate labels and lower contaminant levels. Third, keep the dose moderate. Most studies in non-pregnant adults use 2.5 to 10 grams per day, and there’s no evidence that higher doses offer greater benefits.
Finally, consider whether you actually need a supplement at all. If you’re eating adequate protein from varied sources, you’re already getting the amino acids that collagen provides. Bone broth, slow-cooked meats, and fish with skin are naturally rich in the same glycine and proline found in collagen powders, without the uncertainty that comes with a supplement that hasn’t been studied in pregnancy.