Common Myths About Hair Growth That Keep Circulating Online

Hair grows from follicles beneath the scalp at a rate determined largely by biology, not by what happens to the ends. Trimming removes split ends and prevents breakage from traveling up the shaft, which helps hair appear longer and healthier over time — but it has no effect on the rate of growth itself. This myth likely persists because people who trim regularly also tend to maintain hair health, making length retention more visible.

The "100 strokes" rule is a holdover from an era before modern hair care science. While gentle brushing does distribute natural scalp oils and can improve shine modestly, overdoing it — especially on dry or chemically treated hair — causes friction, cuticle damage, and breakage. Brush enough to detangle and style, using a wide-tooth comb or soft-bristle brush suited to your hair type. For more on habits that erode hair health gradually, see grooming habits that quietly damage hair.

This myth conflates surface coverage with internal biology. Follicles are nourished via blood vessels, not ambient air. A hat would need to be so tight it visibly restricted circulation — an unrealistic scenario for normal headwear — to have any impact. Genetics, hormones, and health conditions are the established drivers of follicle function and hair loss patterns.

Biotin, collagen, and similar supplements are heavily marketed for hair growth. The evidence base, however, is narrow: supplementation tends to benefit individuals with documented deficiencies in specific nutrients like iron, vitamin D, or zinc. For people with adequate nutritional status, adding more of these nutrients does not appear to meaningfully accelerate growth or increase density. A healthcare provider can test for deficiencies before you invest in supplements.

Genetics do play a major role in long-term hair patterns, but acute or prolonged stress can push a larger-than-normal proportion of follicles into the resting (telogen) phase simultaneously, leading to noticeable shedding weeks or months later. This is typically reversible once the stressor resolves. Understanding the difference between stress-related shedding and clinical hair loss matters — learn how to tell them apart.

Over-washing can actually strip the scalp of sebum, prompting oil glands to compensate by producing more — a cycle that worsens the problem. Scalp oiliness varies widely across individuals and is influenced by factors well beyond hygiene habits. For a more detailed look, explore the real reasons your scalp gets oily so fast.