Why Do Some People Get Stretch Marks and Others Don't?

Two people gain the same amount of weight during pregnancy, and one develops visible stretch marks while the other doesn’t. This isn’t random, and there’s now real, large-scale genetic research explaining a meaningful part of why.

What the genetics research found

A study by 23andMe analyzed genetic data and survey responses from more than 670,000 consented research participants, identifying 544 distinct genetic markers associated with stretch mark susceptibility.

The sample size makes this an important piece of evidence that genetic susceptibility matters, but association studies do not mean those markers fully determine who will or will not develop stretch marks.

What happens when a stretch mark forms

Stretch marks involve structural changes in the dermis during periods of rapid growth or stretching. Describing them as simple “tears” can be misleading because hormones, collagen organization, and tissue remodeling also appear to play a role. The result is the visible line we recognize as a stretch mark, appearing pink or purple initially before typically fading to a lighter, silvery tone over time.

This tearing happens in the dermis, not on the visible surface, which is part of why stretch marks don’t respond to surface-level treatments the way many people expect.

Why genetics determines who tears and who doesn’t

The exact reason isn’t fully understood even with the genetic markers identified, but one working theory is that when skin is stretched rapidly, the resulting microscopic damage doesn’t heal as effectively in some people as others, based on how their specific collagen structure responds and repairs.

This helps explain why family history is one of the more consistently observed risk factors, since genetic variation in collagen structure and healing response would naturally run in families.

Does this mean prevention products don’t work

Most topical prevention products, oils, creams, and lotions, only moisturize the outer epidermis and don’t reach or meaningfully reinforce the dermis where the actual tearing occurs.

This is worth knowing honestly rather than assuming a specific expensive cream will prevent what’s largely a genetically influenced, deeper structural process. Keeping skin generally healthy and hydrated has some value, but it doesn’t override genetic predisposition.

What other factors increase risk alongside genetics

Rapid weight gain, whether from pregnancy, puberty growth spurts, or significant muscle or fat gain, is the most consistent trigger, since it’s the actual stretching event that reveals whatever genetic predisposition is present.

Family history specifically matters here too. If a parent had noticeable stretch marks, that’s a real, statistically meaningful signal about your own likely genetic predisposition.

Does this affect men as well as women

Yes, though stretch marks are more commonly discussed in the context of pregnancy. Rapid muscle gain in bodybuilders, weight fluctuations, and puberty growth spurts can all trigger stretch marks in men through the same underlying mechanism.

Can existing stretch marks be reversed

Not fully, since they represent a real structural change in the dermis rather than a surface-level pigmentation issue. Some treatments, including certain lasers and microneedling performed by a professional, can improve their appearance meaningfully, though complete reversal isn’t realistic given the underlying tissue change involved.

Does slower weight gain actually reduce risk

There’s a reasonable, physically logical basis for this. Giving skin more time to adapt to gradual stretching, rather than very rapid change, may reduce the mechanical stress that triggers tearing, though this doesn’t override a strong genetic predisposition entirely.

A realistic way to think about prevention

Given the significant genetic component identified in research, treating prevention products as a modest, supportive habit rather than a guaranteed solution sets more realistic expectations. Gradual weight changes when possible, combined with basic skin hydration, address the factors actually within your control.

Frequently asked questions

Do stretch marks always fade completely on their own? They typically lighten from an initial pink or purple tone to a paler, more silvery color over time, but they don’t usually disappear entirely without some form of active treatment.

Is there a specific gene responsible for stretch marks? No single gene explains this. The 23andMe research identified 544 separate genetic markers collectively associated with stretch mark risk, reflecting a complex, multi-gene trait rather than one simple genetic switch.

Does skin elasticity in general predict stretch mark risk? There’s a plausible connection, since stretch marks relate directly to how well skin’s elastic and collagen fibers accommodate rapid change, though elasticity alone doesn’t capture the full genetic picture identified in the research.

Can retinol help fade existing stretch marks? Some evidence suggests retinol may modestly improve the appearance of early-stage, still-reddish stretch marks by supporting collagen production, though it’s generally less effective on older, already-faded marks.

Genetics explains more than most people assume

Real, large-scale genetic research has identified hundreds of specific markers linked to stretch mark susceptibility, confirming what many people have long suspected from family patterns: genetics plays a substantial, measurable role in who develops visible stretch marks and who doesn’t.

Weight gain, pregnancy, and growth spurts are the triggering events, but your genetic susceptibility is one important factor in whether stretching leaves visible marks, and current evidence does not support promising that a topical cream can reliably prevent them.