What can research tell us about protecting hair grafts before placement?

A hair follicle graft is briefly separated from its blood supply between removal and placement. That makes hydration, storage conditions and elapsed time sensible subjects to ask about. But what do published studies actually tell us: can they identify a best solution, a safe time limit, or a likely result for one person?

The evidence is mixed in design and strength. Laboratory studies show that drying and some storage conditions can change follicle behaviour in culture. A small experiment suggests a preservation medium may matter for unusually small, longitudinal grafts. One randomised clinical study compared two holding solutions and reported differences in postoperative shedding in a subgroup, while finding no difference in final graft survival. None of these findings establishes a universal protocol or predicts an individual transplant outcome.

Why storage matters, and what “viability” means

After extraction, a graft no longer receives oxygen and nutrients through its normal circulation. Researchers have therefore studied drying, storage temperature, duration and solution. Their measurements are not interchangeable. A follicle that elongates in culture, a tissue sample that stains as viable, a change in gene expression, postoperative shedding and the eventual number of growing hairs are different outcomes.

Laboratory assays can help compare conditions under a defined protocol. They cannot, on their own, tell a patient how many grafts will grow after surgery. Clinical results also depend on factors these storage experiments did not test, including the individual’s donor and recipient areas and the wider operative process.

Dry exposure: a measurable laboratory effect

Hwang and colleagues studied scalp follicles from 20 men aged 29–45 years (mean 38) undergoing hair transplantation at a university centre in Daegu, South Korea. Of 1,300 anagen follicles collected, 500 were allocated to a dry-gauze experiment: 100 follicles per exposure period, left at room temperature for 0, 5, 10, 20 or 30 minutes. The investigators then assessed follicle elongation during organ culture.

Elongation was observed in 96% of follicles without dry exposure, 94% after 5 minutes, 94% after 10 minutes, 83% after 20 minutes and 68% after 30 minutes. The paper does not provide confidence intervals for these percentages. The result is a laboratory signal that prolonged drying can impair this culture endpoint. It is not a countdown for a procedure, a measurement of routine clinical handling, or a forecast of a patient’s growth. [1]

Keeping extracted grafts from drying unnecessarily is a reasonable preservation concern. The cited experiments did not compare specific staff handling workflows or show that one handoff system produces better patient outcomes.

Storage time and temperature: the protocol changes the result

In the second part of the same study, 800 follicles were placed in saline across eight groups: 100 in each five-minute control condition at room temperature or 4°C, and 100 for each of 6, 24 or 48 hours at each temperature. Following storage, follicles were cultured for seven days. Reported survival was 95%, 92%, 40% and 34% for the five-minute, 6-hour, 24-hour and 48-hour room-temperature groups; at 4°C, the corresponding figures were 96%, 94%, 76% and 50%. No confidence intervals were reported. These long experimental storage periods do not define the safe duration of a real operation, and the culture endpoint is not a clinical survival rate. [1]

A separate randomised in-vitro experiment used 240 anagen follicles from 10 healthy men. Half were stored for five hours at 26°C and half at 1°C; both groups were then cultured for 10 days. Survival was 87% at 26°C and 88% at 1°C. Mean 10-day growth was 2.68 mm and 2.54 mm, respectively. The authors reported no statistically significant difference. This single comparison does not show that cooling never matters; it shows that this experiment did not detect a difference under its particular five-hour conditions. [2]

The two experiments should not be collapsed into a simple rule that colder is always better. They used different storage durations and protocols. The evidence does not settle a universal temperature, solution or maximum time outside the body for every graft and procedure.

Holding solutions: promising comparisons with important limits

In a 1998 laboratory study, Raposio and colleagues randomly allocated 200 follicles from 10 men to five hours in saline or a solution containing ATP-magnesium chloride and deferoxamine mesylate, then assessed them in 10-day culture. The abstract reports survival of 87% with saline and 98% with the enriched medium, with a statistically significant difference. It gives neither the exact P value nor a confidence interval. This is evidence about one formulation and a laboratory endpoint, not proof that a particular commercial product increases a person’s final hair growth. [3]

Gho and Neumann examined 90 small grafts from three patients: each patient contributed 15 grafts measuring 0.6 mm and 15 measuring 0.7 mm. After four hours in saline, Ringer’s lactate or a solution developed by Hair Science Institute, where Gho was employed, viability was assessed semi-quantitatively using trypan blue staining. The article reports better viability with the institute-developed solution than with the two comparators, but does not provide a numerical effect estimate in the text. The specialised partial longitudinal grafts, tiny sample and institute affiliation sharply limit how far the finding can be generalised. It is not a neutral ranking of holding products for routine procedures. The authors disclosed that Gho was an institute employee, Neumann declared no conflict, the study used institutional resources and the institute paid the article-processing charge. [4]

A 2019 ex-vivo study enrolled 38 men aged 18–55 undergoing FUE and compared gene expression in freshly dissected follicles with follicles stored for six hours. For the temperature comparison, samples were held in saline or dermal-papilla cell growth medium at room temperature or 4°C; for the media comparison, samples were stored at 4°C in saline, cell medium, Hypothermosol, ATPv-supplemented Hypothermosol, ATPv-supplemented saline or autologous platelet-rich plasma. The authors measured gene-expression markers by quantitative PCR, with sample sizes varying by comparison (figures commonly used four to seven patients), and used trypan-blue staining in small viability comparisons. The paper reports that room-temperature storage in cell medium increased inflammatory and apoptosis markers and repressed HEY1 relative to 4°C. After six hours at 4°C, ATPv-supplemented saline preserved several growth-signalling markers; however, staining did not show a clear viability improvement for that solution. The authors’ favourable interpretation therefore rests chiefly on molecular markers, not demonstrated patient hair growth. The study did not report a clinical outcome, and its small, variable subgroup sizes limit certainty. [5]

These comparisons help explain why researchers continue to study preservation. They do not establish that an experimental solution is available, appropriate or superior for a particular person, nor that a named service listing includes the studied protocol.

What the randomised clinical study adds

Zhou and colleagues enrolled 240 hair-transplant patients in a randomised controlled clinical study at a hospital in Guangzhou, China. Grafts were stored in either histidine-tryptophan-ketoglutarate solution with adenosine triphosphate and deferoxamine (HTK-AD) or Ringer solution. The team also used tissue staining to assess graft morphology and cell viability. The accessible abstract does not report the group sizes, patient characteristics, allocation procedure, blinding, detailed follow-up schedule or confidence intervals.

Among patients receiving at least 3,000 grafts, postoperative shedding was reported in 73.81% of the HTK-AD group and 95% of the Ringer group (p<0.05). The abstract also reports later shedding onset, less shedding, shorter shedding duration and earlier regrowth with HTK-AD, each at p<0.05, but does not quantify those differences or give subgroup denominators. Most importantly, it states that final graft-survival rates did not differ between groups. Shedding and final survival are separate outcomes; the reported shedding results must not be presented as proof of higher final survival. The accessible record is not enough to judge the size or precision of the subgroup effects fully. [6]

The authors conclude that HTK-AD was superior to Ringer solution for preservation, but the abstract’s own final-survival result is unchanged between groups. This one study of one formulation cannot establish a benefit for other solutions, clinics, graft counts or workflows. The accessible abstract does not give funding or conflict-of-interest details; the full disclosure text was not available for this review.

What a patient can take from the evidence

The most defensible practical point is limited: avoid unnecessary drying, and ask how the clinical team organises graft storage and the sequence from extraction to placement. The research does not identify a universal “safe” time outside the body, prove that a particular temperature or product is best in every case, or provide a personal survival percentage.

When a team discusses a “survival rate”, ask which outcome it means, how that outcome was measured and when it was assessed. A culture percentage, a staining score, the proportion of patients who report shedding and a final count of growing hairs answer different questions. An explanation should make those distinctions clear rather than turning a laboratory figure into a promise.

Questions to ask in a consultation

• Who is responsible for the grafts at each stage, from extraction until placement?
• How are grafts kept from drying while they are awaiting placement, and where are they stored?
• How does the team coordinate extraction and placement, and what happens if the session takes longer than expected?
• If a solution or temperature is discussed, what evidence supports its use for the proposed procedure, and does that evidence measure laboratory viability or patient outcomes?
• When someone quotes a graft “survival” figure, what exactly was counted, in which patients, and at what follow-up point?
• Which parts of the plan are specific to my donor area, recipient area and pattern of hair loss?

For cost planning, you can compare hair transplant costs in Turkey and ask what a quoted amount covers. The hair transplant packages directory is service information; its listings do not show that a particular research protocol is included or that one package produces better clinical results. Just Clinic Istanbul is an independent marketing and lead-generation platform, not a healthcare provider or medical tourism intermediary. Enquiries may be shared with authorised healthcare partners with your consent.

Limitations and unanswered questions

Most of the evidence here comes from small laboratory experiments, with different graft types, storage periods, media and endpoints. Percentages from one protocol cannot be compared as if they came from a single trial. Confidence intervals and detailed statistical information are absent from several abstracts. The small study of partial longitudinal grafts was conducted by Gho, who was employed by the institute that developed the tested solution; Neumann was affiliated with Erasmus University. The 2019 molecular study included small, varying patient subsets, and its findings concern gene-expression markers rather than clinical hair growth. The clinical trial is more directly relevant to patients, but its abstract leaves key design and subgroup details unavailable and reports no final-survival difference.

Better clinical research would report allocation methods, baseline characteristics, group sizes, graft counts, prespecified outcomes, follow-up times and uncertainty estimates. Until such evidence is available, these studies support careful questions about process; they do not justify a universal storage recipe, a product ranking or a prediction for an individual.

References

1. Hwang S-J, Lee J-J, Oh B-M, Lee S-J, Kim D-W, Kim J-C, Kim M-K. The Effects of Dehydration, Preservation Temperature and Time on the Hair Grafts. Annals of Dermatology. 2002 Jul;14(3):149–152. Published online 15 March 2016. doi: 10.5021/ad.2002.14.3.149. Open full text.
2. Raposio E, Cella A, Panarese P, Mantero S, Nordström REA, Santi P. Effects of Cooling Micrografts in Hair Transplantation Surgery. Dermatologic Surgery. 1999 Sep;25(9):705–707. First published 24 December 2001. doi: 10.1046/j.1524-4725.1999.98287.x. PMID: 10491061. Abstract reviewed; full text was unavailable.
3. Raposio E, Cella A, Panarese P, Nordström REA, Santi P. Power Boosting the Grafts in Hair Transplantation Surgery: Evaluation of a New Storage Medium. Dermatologic Surgery. 1998 Dec;24(12):1342–1345; discussion 1346. Issue and version of record published online 8 May 2014. doi: 10.1111/j.1524-4725.1998.tb00012.x. PMID: 9865201. Abstract reviewed; full text was unavailable.
4. Gho CG, Neumann HAM. The Influence of Preservation Solution on the Viability of Grafts in Hair Transplantation Surgery. Plastic and Reconstructive Surgery Global Open. 2014 Jan 6;1(9):e90; eCollection 2013 Dec. doi: 10.1097/GOX.0000000000000032. PMID: 25289284; PMCID: PMC4174110. Full text reviewed.
5. Castro AR, Portinha C, Logarinho E. Impact of Preservation Solutions on the Trichogenicity of Hair Micrografts Ascertained by Dermal Papilla Gene Expression. Dermatologic Surgery. 2019 Dec;45(12):1649–1659. doi: 10.1097/DSS.0000000000001895. PMID: 30865019. Full text reviewed.
6. Zhou Y, Zhang J, Fan Z, Hu Z, Miao Y. Evaluation of a Novel Graft-Holding Solution in Hair Transplantation: A Randomized Controlled Clinical Study. Dermatologic Surgery. 2023 Jul;49(7):675–681. Published online 7 April 2023. doi: 10.1097/DSS.0000000000003799. PMID: 37036372. Abstract reviewed; publisher lists supplemental digital content, which was not accessed.