Whether or not you get stretch marks comes down mostly to genetics, with hormones, age, and nutrition playing supporting roles. In a study of over 1,000 pregnant women, 41% never developed stretch marks at all, despite the significant skin stretching that pregnancy demands. The difference between those who do and those who don’t isn’t about willpower or skincare routines. It’s largely written into your DNA.
Genetics Are the Strongest Factor
Genome-wide studies have identified several genes that directly influence whether your skin tears under stress or stretches smoothly. The most significant is a variant near the ELN gene, which provides the blueprint for elastin, the protein that lets your skin snap back after being stretched. A specific variant located near this gene (rs7787362) was strongly associated with stretch mark susceptibility, with people carrying the protective version being about 16% less likely to develop them.
Other genes in the mix include HMCN1, which codes for a protein involved in anchoring layers of tissue together, and SRPX, along with genes tied to skin barrier function and connective tissue structure. What all of these genes have in common is that they influence either how stretchy your skin is, how well its layers hold together, or how efficiently your body repairs micro-damage in the dermis, the thick middle layer of skin where stretch marks form. If you inherited favorable versions of these genes, your skin can withstand more mechanical stress before the collagen and elastin fibers in your dermis rupture. That’s the core reason some people sail through pregnancy, growth spurts, or significant weight changes without a single mark.
How Hormones Tip the Balance
Stretch marks aren’t just about how fast your skin stretches. They’re also about what’s happening chemically inside that skin while it stretches. Cortisol and related stress hormones (glucocorticoids) play a major role. These hormones ramp up protein breakdown and reduce collagen synthesis, effectively weakening the scaffolding in your dermis right when it needs to be strongest. People with naturally lower cortisol levels, or whose skin cells are less sensitive to cortisol’s effects, have a built-in advantage.
During pregnancy specifically, estrogen, relaxin, and adrenocortical hormones reduce the adhesiveness between collagen fibers and increase the gel-like ground substance between them. This makes the dermis softer and more prone to tearing under tension. The degree to which these hormones affect your skin varies from person to person, which is another reason two women with identical weight gain during pregnancy can have completely different outcomes. One may have fibroblasts (the cells that build and repair collagen) that keep working efficiently despite hormonal shifts, while another’s fibroblasts slow down significantly.
Why Younger Skin Is More Vulnerable
This one surprises most people. Younger skin is actually more prone to stretch marks, not less. In studies of pregnant women, those who developed stretch marks were significantly younger, averaging about 26.5 years old compared to 30.5 for those who didn’t. The difference was statistically clear.
The likely explanation is that collagen fibers become more cross-linked and rigid with age. While that rigidity contributes to wrinkles later in life, it also means the dermis is less likely to tear apart under stretching forces. Younger skin is more pliable but also more fragile at the structural level. It deforms more easily, which means it’s more likely to reach the breaking point. This is why teenagers going through growth spurts develop stretch marks so frequently, and why women who have their first pregnancy in their early twenties tend to get more marks than those who wait until their thirties.
Collagen Production and Vitamin C
Your body’s ability to build and maintain collagen plays a direct role in how well your skin resists tearing. Collagen makes up roughly 75% of the dermis by dry weight, forming the dense mesh of fibers that gives skin its tensile strength. Vitamin C is essential to this process. It acts as a required co-factor for the enzymes that stabilize collagen molecules and also stimulates fibroblasts to produce more collagen in the first place.
Cell studies have shown that when vitamin C is absent, both total collagen production and the cross-linking that strengthens collagen fibers drop significantly. On the other end of the spectrum, supplementation with even modest amounts of vitamin C increased collagen production by 43% to 57% and elastin production by 20% to 31% in one study. Smokers, who tend to have depleted vitamin C levels, show impaired collagen formation that improves after quitting. While no study has directly proven that higher vitamin C intake prevents stretch marks, the biological chain is clear: less vitamin C means weaker collagen, and weaker collagen means skin that tears more easily under stress.
Zinc also supports collagen synthesis and wound repair, though the evidence linking it specifically to stretch mark prevention is less direct. What matters practically is that people whose diets consistently support collagen production are giving their skin better raw materials to work with during periods of rapid stretching.
The Rate of Stretching Matters
Even with perfect genetics, there’s a mechanical threshold. Stretch marks form when skin expands faster than the dermis can remodel itself to accommodate the new shape. Rapid weight gain, sudden growth spurts during puberty, and pregnancies with larger babies or excess amniotic fluid all increase the speed and degree of stretching.
People who gain weight gradually give their fibroblasts time to lay down new collagen and elastin, reinforcing the dermis as it expands. Those who gain rapidly overwhelm this repair process. This is why stretch marks are associated with both rapid weight gain and rapid weight loss: in both cases, the skin experienced a period of fast change that outpaced its ability to adapt. Someone with genetically robust collagen and elastin production can tolerate a faster rate of stretching before damage occurs, which is another way genetics and mechanical forces interact.
What You Can and Can’t Control
The honest answer is that genetics load the dice heavily. If your parents went through puberty, pregnancy, or weight fluctuations without stretch marks, you’re more likely to do the same. No cream or oil has been proven in rigorous trials to prevent stretch marks, despite the size of the market for these products. The structural tearing happens deep in the dermis, well below where topical products penetrate.
What you can influence is the environment your skin is working in. Maintaining adequate vitamin C and zinc intake supports the collagen machinery. Keeping weight changes gradual rather than sudden gives your skin time to adapt. Staying hydrated helps maintain the ground substance between collagen fibers. And avoiding prolonged use of corticosteroid medications, when medically possible, prevents the chemical weakening of your dermal structure. None of these guarantees you’ll avoid stretch marks, but they reduce the mechanical and biochemical stress on skin that’s already genetically predisposed to tearing.