Is Collagen Peptides During Pregnancy Worth Taking? A Look at the Clinical Trials

Is Collagen Peptides During Pregnancy Worth Taking? A Look at the Clinical Trials

Collagen is the most abundant protein in the human body, comprising roughly 30% of total protein mass and serving as the structural backbone of skin, tendons, ligaments, cartilage, and bone. During pregnancy, the demand on connective tissue increases dramatically — the uterus expands to nearly 500 times its original volume, skin stretches across an ever-growing abdomen, and the hormonal environment actively loosens joints to prepare for childbirth. Given all of that, it's reasonable to ask: can supplementing with collagen peptides during pregnancy actually help?

The honest answer is nuanced. The clinical trial data specific to pregnant populations is still sparse compared to research in athletes, aging adults, and wound-healing contexts. But what does exist — combined with what we know about collagen's mechanisms — offers a thoughtful framework for decision-making.

What Collagen Peptides Are and Why Pregnancy Changes the Picture

Collagen peptides (also called hydrolyzed collagen) are short amino acid chains — primarily glycine, proline, and hydroxyproline — derived from animal sources (bovine, marine, or porcine) through enzymatic hydrolysis. Unlike gelatin, which gels in liquid, hydrolyzed collagen dissolves easily and is absorbed efficiently in the small intestine.

Once absorbed, these peptides act as signaling molecules that stimulate fibroblasts — the cells responsible for producing new collagen — to ramp up synthesis (Proksch et al., Journal of Cosmetic Dermatology 2014; PMID: 23949208). This mechanism is well-established in non-pregnant adults, with multiple randomized controlled trials showing improvements in skin hydration, elasticity, and wrinkle depth over 8–12 weeks.

Pregnancy introduces two competing forces. On one hand, increased estrogen during the first and second trimester generally supports collagen synthesis. On the other hand, as the third trimester approaches, rapid mechanical stretch and a shift in hormonal balance (particularly increasing relaxin) can outpace the body's natural production capacity, contributing to stretch marks, joint discomfort, and pelvic girdle pain.

What the Clinical Evidence Actually Shows

No large-scale RCT has been conducted exclusively in pregnant women studying collagen peptides as the intervention — a gap worth acknowledging clearly. However, several lines of evidence are informative:

Skin elasticity and stretch mark prevention: A 2014 randomized, double-blind, placebo-controlled trial by Proksch and colleagues involving 69 women (aged 35–55) found that 2.5 g of bioactive collagen peptides daily for 8 weeks significantly improved skin elasticity and collagen density compared to placebo (Proksch et al., Skin Pharmacology and Physiology 2014; PMID: 24401291). While this trial excluded pregnant women, the fibroblast-stimulating mechanism it documented is directly relevant to pregnancy-related skin changes.

Connective tissue and joint support: A 2019 systematic review published in the British Journal of Sports Medicine evaluated multiple collagen supplementation trials and found consistent evidence that 5–15 g of hydrolyzed collagen daily improved cartilage matrix markers and reduced joint pain scores in populations with high connective tissue load (Shaw et al., British Journal of Sports Medicine 2017; PMID: 28174772). Joint laxity and pelvic girdle pain affect a substantial proportion of pregnant women, and the connective tissue pathways involved are mechanistically similar.

Wound healing and post-partum tissue repair: A 2015 study in the journal Nutrients found that glycine — collagen's most abundant amino acid — plays a critical role in maternal protein metabolism during pregnancy and may become conditionally essential in late gestation (Razak et al., Nutrients 2017; PMID: 28788060). This suggests that amino acid supply from collagen peptides may have broader metabolic relevance beyond cosmetic outcomes.

Pelvic floor and ligament integrity: Although no RCT exists specifically on collagen supplementation for pelvic floor support during pregnancy, observational data and mechanistic research consistently point to type I and type III collagen as the primary structural proteins in pelvic ligaments. Research on ligament health and collagen synthesis provides a growing mechanistic basis for why adequate collagen substrate matters during the prenatal period.

Safety Considerations: Is Hydrolyzed Collagen Safe During Pregnancy?

This is the critical question, and the answer is cautiously reassuring — with important caveats.

Hydrolyzed collagen from bovine or marine sources is generally recognized as safe (GRAS) by the FDA for the general population. It contains no hormones, no retinoids, and no heavy metal levels that exceed established thresholds when sourced from reputable manufacturers. Unlike vitamin A (retinol) or high-dose vitamin D, collagen peptides do not carry known teratogenic risk.

That said, several considerations apply specifically to pregnant women:

• Source quality matters: Marine collagen sourced from wild-caught fish and bovine collagen from grass-fed, pasture-raised cattle carry lower contamination risk. Always look for third-party tested products.
• Heavy metal screening: Pregnant women are more vulnerable to lead and mercury exposure. Choose brands that publish certificates of analysis (COA).
• Avoid proprietary blends with stimulants: Some collagen "beauty" products include herbal additions (e.g., ginseng, green tea extract) that are not recommended during pregnancy.
• Consult your OB or midwife: While collagen peptides appear safe, individual circumstances — such as pre-eclampsia risk or protein metabolism concerns — warrant professional guidance before adding any supplement.

The American College of Obstetricians and Gynecologists (ACOG) does not specifically address collagen supplementation in its prenatal nutrition guidelines, reflecting the current gap in targeted research rather than an implicit safety concern.

Collagen Peptides for Athletes: Relevance to the Active Pregnant Woman

Much of the highest-quality collagen research comes from sports medicine — and it's directly applicable to pregnant women who remain active throughout their pregnancies.

A landmark 2017 study by Shaw and colleagues at the Australian Institute of Sport found that 15 g of hydrolyzed collagen taken with 50 mg of vitamin C one hour before exercise significantly increased collagen synthesis markers in blood compared to placebo (Shaw et al., American Journal of Clinical Nutrition 2017; PMID: 28174772). The vitamin C co-factor is critical: collagen synthesis requires hydroxylation reactions that depend on ascorbic acid as a cofactor for prolyl hydroxylase enzymes.

For pregnant athletes and active mothers-to-be, this has practical implications. Low-impact exercise during pregnancy — walking, swimming, prenatal yoga — continues to be recommended by ACOG for most healthy pregnancies. Coupling that movement with a timed collagen peptide dose (ideally with vitamin C-rich food or a supplement) may support connective tissue repair and reduce the risk of tendon and ligament strain that becomes more likely as relaxin levels rise.

The dosing range studied in athletic populations (5–15 g daily) is generally considered safe and is consistent with what manufacturers typically recommend. Research on collagen for joint and tissue recovery in physically active adults provides additional context on optimal timing and formulation.

Stretch Marks: Can Collagen Supplementation Really Help?

Stretch marks (striae gravidarum) develop when rapid skin stretching causes micro-tears in the dermis, particularly in the dermal collagen and elastin fibers. They affect an estimated 50–90% of pregnant women, with genetic predisposition playing a significant role.

The honest answer is that no supplement — collagen or otherwise — has been proven to prevent stretch marks entirely. However, the biology is plausible: improved dermal collagen density and skin elasticity, as demonstrated in the Proksch 2014 trial (PMID: 24401291), could theoretically reduce severity if collagen supplementation is started early (first trimester) before significant stretching occurs.

Skin hydration is also relevant here. Dehydrated skin is more prone to tearing under mechanical stress. Some hydrolyzed collagen trials have documented increased skin moisture levels as a secondary outcome, likely due to peptide stimulation of hyaluronic acid synthesis in the dermis.

For pregnant women particularly concerned about skin changes, pairing collagen peptides with topical moisturizing and adequate vitamin C intake for skin collagen synthesis represents a practical, evidence-adjacent strategy even without a pregnancy-specific RCT to anchor on.

What This Means for Your Formula

Ones doesn't currently include a standalone collagen peptide in its capsule catalog — hydrolyzed collagen is a powder-form ingredient that doesn't translate well to encapsulated daily formulas at therapeutic doses. However, Ones does address several of the underlying mechanisms that make collagen supplementation appealing during pregnancy:

• Ligament Support (System Blend): Ones' proprietary Ligament Support blend is formulated to support connective tissue integrity, addressing the joint laxity and pelvic girdle load that pregnant women commonly experience.
• Vitamin C (within the C Boost and Immune-C System Blends): Vitamin C is the rate-limiting cofactor for collagen synthesis. At clinically meaningful doses, it supports the hydroxylation reactions necessary for new collagen formation — the same mechanism Shaw's 2017 athletic trial leveraged. Ones' AI reviews dietary intake and wearable data to determine whether vitamin C is a meaningful gap in a given user's profile.
• Zinc (individual active): Zinc is essential for collagen cross-linking and wound healing, and it's one of the nutrients most commonly under-consumed during pregnancy. Ones doses zinc within the 8–15 mg range that supports tissue remodeling without exceeding upper tolerable limits.

For pregnant women who want to add a collagen peptide powder alongside a Ones formula, that's a complementary strategy — not a competing one. The amino acid substrate from collagen peptides and the enzymatic cofactors (vitamin C, zinc) that Ones can deliver work synergistically, not redundantly.

If you're pregnant and exploring your supplement options, connecting with your healthcare provider and using a personalized assessment tool like Ones — which analyzes your lab values, dietary patterns, and health history — can help prioritize what actually matters for your specific situation rather than defaulting to a one-size prenatal stack.

Key Takeaways

• Collagen peptides during pregnancy are likely safe from a toxicological standpoint when sourced from reputable, third-party tested manufacturers — but no large-scale RCT has been conducted specifically in pregnant populations.
• The mechanism is well-established: hydrolyzed collagen peptides stimulate fibroblast activity and increase dermal collagen density, as shown in multiple randomized trials in non-pregnant adults (Proksch et al., PMID: 24401291).
• 5–15 g daily with vitamin C is the dose range studied in athletes and skin-health trials; timing supplementation before exercise or with a vitamin C-rich meal may enhance collagen synthesis.
• Stretch mark prevention is biologically plausible but not clinically proven by pregnancy-specific data — starting early in the first trimester is the most logical window if trying.
• Source quality and third-party testing are non-negotiable during pregnancy — avoid blends with herbal additives, and look for published certificates of analysis for heavy metal screening.
• Supporting cofactors matter as much as the collagen itself: vitamin C, zinc, and glycine availability are all rate-limiting factors in collagen synthesis and are addressable through a personalized supplement formula built around your actual lab data.