Hair oils: the category where price barely matters
I measured 2,238 price changes across 161 hair oils and compared each one against the products that held their price. Both directions move rank far less than the price does — a 10 percent discount bought about 5 percent of rank, a 10 percent increase cost about 3 percent. Both ranges stay well clear of one for one. Of the five categories measured so far, this is the one where price does the least.
In short
- A 10 percent discount improved rank by about 5 percent (range 3 to 6). Less than half of what the discount gives away.
- A 10 percent increase cost about 3 percent of rank (range 2 to 5) — the mildest penalty measured in this series.
- Beyond a 15 percent increase, the cost stops growing. A rise of 15 to 25 percent and one above 25 percent cost the same 16 to 17 percent of rank.
- No segment pattern: all three price groups sit far below one for one, and the middle group is the weakest of the three.
- Competitors are the slowest to answer of any category here — a median of two days, and fewer than half of the answers on the same day.
Price cuts
A 10% cut improved rank by roughly 3 to 6 percent.
Price increases
A 10% increase cost roughly 2 to 5 percent of rank.
Weak in every price group, and no order to it
Every one of the six figures in the chart above sits below one for one, and all of them stay clear of it. That is the finding: in hair oils, a price move produces a rank move less than half its own size, whichever direction it goes and whatever the product costs.
There is no order to the price groups either. The middle group has the weakest discount response (0.34), the budget group the strongest (0.57), and all three ranges overlap heavily. Whatever separates a €9 hair oil from a €35 one, it is not how buyers respond to its price.
For a brand in this category the reading is unusually simple. Discounting is close to pointless — a cut buys back less than half of the margin it gives away. Raising prices is close to free: a 10 percent increase costs 3 percent of visibility. If costs rise, this is a category where they can be passed on.
The full picture
01 · 1 · Does the size of the price change matter?
Up to a point, and then it stops.
Rank after price changes of different sizes
The discount side climbs slowly and stays shallow: 9 percent better rank for a small cut, 14 percent for a moderate one, 19 percent for a quarter off or more. In eye creams a moderate discount already bought 26 percent. Here the deepest discounts do less than a middling one does elsewhere.
The increase side has a ceiling, and it is a useful one. A rise of 15 to 25 percent cost 16 percent of rank; a rise above 25 percent cost 17 percent. Beyond roughly 15 percent, going further costs nothing extra in visibility. That is the mirror image of the discount ceiling seen in other categories, and it is rarer: it means a large price correction here is barely more expensive than a small one.
02 · 2 · Will competitors follow?
Slowly, and less than anywhere else in this series.
Time until the first competitor answers a price cut
Across 3,852 price changes from 168 products, rivals answered a cut 6 percent more often than their own repricing rhythm would produce and an increase 13 percent more often. The median first answer came after two days, and fewer than half of all answers landed on the same day — against six in ten in eye creams and three in four in face serums. This is the least automated market in the series.
03 · 3 · Where could a new product enter?
One price range qualifies, and its evidence is thin.
Competition and demand by price range
Only one of twelve price ranges clears the demand baseline, and it clears it exactly: €10.85 to €12.56, where a third of the twelve products rank in the top third. It has a typical review count of 128 and prices that hold for about six weeks — but only one recent entrant, and that launch is too young to judge. So the corridor is a plausible place to start rather than a proven one, and I would treat it as such.
Two other ranges are worth naming for the opposite reason. €22.58 to €26.15 has the best entrant record in the category — four judged launches, three of them winning — but only 18 percent of its products reach the top third, so it cannot establish that buyers are there at that price. And €8.09 to €9.37 has a typical review count of 2,227: that band is defended by established brands, not open ground.
For the category as a whole: of 289 priced products, 90 launched within the last two years, 23 have reached the top third and 3 disappeared. Hair oils take newcomers about as readily as sunscreen does.
04 · 4 · What the market looks like underneath
A crowded shelf with a lot that does not belong on it.
Of 3,904 price changes found, 651 had another change from the same product running in the same window, 398 had too little ranking data, 227 coincided with a burst of new reviews and 223 with a stockout. 205 events were dropped because the product was already sliding before the price came down, and 212 because too few comparable products held their price — the highest share of that exclusion in the series, which is what a market of many small brands looks like.
The category boundary is loose. 60 of the 349 products do not sit in the hair-oil branch of Amazon's own category tree, and the raw listing contained mouthwash, sanitary pads and nappies before curation. Observed price changes run from 83 percent off to more than eight times the price.
Data appendix
349 products on amazon.de, taken from the hair-oil listing and then narrowed: no shampoos, conditioners or masks, no styling products, no beard or men's lines, no children's lines, no body, face or nail oils, no multipacks or gift sets, nothing below €8 or above €50, container sizes between 25 and 250 ml where stated, and at most three listings per brand so that a single catalogue cannot dominate the control groups. Only products with at least 20 reviews were kept. Category membership is taken from Amazon's own listing rather than from keywords in the title, so products such as "Moroccanoil Treatment" or a cold-pressed castor oil sold as hair care remain in the set. Products that Amazon does not place in this branch are flagged automatically and excluded from all figures. The product list is available on request for methodological review.
| Step | Events | Removed because |
|---|---|---|
| Price changes found | 3,904 | at least 5% and €0.30, held for 7 days |
| Gaps in the price history | −132 | the change cannot be located precisely |
| Too little ranking data | −398 | less than 70% of days covered |
| Overlapping price change | −651 | another change from the same product in the window |
| Deal or coupon markers | −0 | none recorded in this set |
| Stockout signals | −223 | rank moves for availability, not price |
| Burst of new reviews | −227 | more than 10% and at least 15 new reviews |
| Listing too young | −122 | less than 60 days of history |
| Too few control products | −212 | fewer than five comparable products held their price |
| Passed every check | 2,471 | an event can fail several checks, so the removals sum to more than the difference |
| Used for the figures | 2,238 | from 161 products, after removing 205 with a pre-existing trend and 28 from other category branches |
price change ≥ 5% and ≥ €0.30, held ≥ 7 days · comparison: 14 days before, days 3–14 after · control products: same category, price moved less than 2%, at least 5 of them · rank coverage ≥ 70% of days · listing older than 60 days · review burst = more than 10% and at least 15 new reviews · ranges are 90%, from a bootstrap clustered by product
Observed price changes: −83.0% to +731.0%. The extreme upper end comes from listings returning to a nominal price after being unavailable; the figures above are read only from the range where changes are dense.
Limits — I measure the ranking, not units sold, in the 14 days after a price change. Results hold only for the price range actually observed. Every figure is for the category as a whole or for one of its three price groups, never for an individual product. Where a range touches the level at which nothing happens, I say so instead of quoting a number.
- 349 products
- 3,904 price changes found
- 2,471 passed every check
- 2,238 used for the figures
- 161 products in the fit set
- ref d95c9e8e
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