An iOS app for GLP-1 and peptide protocols. Log every dose, see what is still circulating, and read your weight through fifteen published smoothing methods.https://peptrend.app/en-ushttps://peptrend.app/blog/weekly-versus-daily-dosing/https://peptrend.app/blog/weekly-versus-daily-dosing/About a week either way. The interval is what differs: a daily tablet ripples by about 10%, while a weekly injection swings by a factor of two.Mon, 21 Sep 2026 00:00:00 GMTdose-loggingdose-loggingpharmacokineticsbioavailabilityoral-glp1https://peptrend.app/blog/peptrend-vs-shotsy/https://peptrend.app/blog/peptrend-vs-shotsy/Shotsy is one of the two largest GLP-1 trackers, and its shot log and site rotation are the better half of it. It names no smoothing algorithm. Checked 18 Sep 2026.Sat, 19 Sep 2026 00:00:00 GMTcomparisonscomparisonshotsydose-loggingsite-rotationhttps://peptrend.app/blog/setting-a-goal-you-can-hit/https://peptrend.app/blog/setting-a-goal-you-can-hit/Peptrend refuses any plan faster than 1.5 lb a week and greys out Save. Where that cap sits against published rates, and how the rate, ETA and deficit are computed.Thu, 17 Sep 2026 00:00:00 GMTgetting-startedgoalsprojectionsenergy-deficitregressionhttps://peptrend.app/blog/plateaus-drawdown-regression/https://peptrend.app/blog/plateaus-drawdown-regression/A stall is only a stall once it clears your own noise. On one user's log the two-morning read and the fitted slope disagreed on direction in 15 of 92 windows.Tue, 15 Sep 2026 00:00:00 GMTquantquantplateaudrawdownregression-to-the-meangoalshttps://peptrend.app/blog/why-a-calculator-should-refuse/https://peptrend.app/blog/why-a-calculator-should-refuse/A unit is a mark on a syringe barrel, so 1 mg has no unit count until you name the barrel. Peptrend divides strength by water, prints mg/mL and stops there.Sun, 13 Sep 2026 00:00:00 GMTreconstitutionreconstitutionapp-review-1-4-2syringe-unitssafetyhttps://peptrend.app/blog/importing-from-apple-health/https://peptrend.app/blog/importing-from-apple-health/One tap reads every body-mass sample Apple Health holds, back to the first. Peptrend writes back only the weigh-ins you type in.Fri, 11 Sep 2026 00:00:00 GMTgetting-startedapple-healthhealthkitimportgetting-startedhttps://peptrend.app/blog/signal-to-noise-on-your-scale/https://peptrend.app/blog/signal-to-noise-on-your-scale/Two weeks is rarely long enough to tell a real change from ordinary scale noise. Work out your own noise-to-signal ratio, then how many days it takes to clear it.Wed, 09 Sep 2026 00:00:00 GMTquantquantsignal-to-noisestatisticsregressionhttps://peptrend.app/blog/reading-the-absorption-curve/https://peptrend.app/blog/reading-the-absorption-curve/Hours to days after the shot — 1 to 3 days for semaglutide, 8 to 72 hours for tirzepatide by the labels. The peak lands at D × F × 2^(−Tmax ÷ half-life).Mon, 07 Sep 2026 00:00:00 GMTdose-loggingpharmacokineticsabsorptiontmaxdose-logginghttps://peptrend.app/blog/rolling-median-when-the-scale-lies/https://peptrend.app/blog/rolling-median-when-the-scale-lies/One 10 lb error moves a 7-value rolling median 0.4 lb and a 7-value moving average 1.43 lb. Double the error and the mean's miss doubles; the median's does not.Sat, 05 Sep 2026 00:00:00 GMTtrend-methodsrolling-medianrobust-statisticsoutliersbreakdown-pointtrend-methodshttps://peptrend.app/blog/peptrend-vs-trendweight/https://peptrend.app/blog/peptrend-vs-trendweight/TrendWeight is web-only and free forever, takes typed weigh-ins or a Withings sync, and publishes every formula it uses. Peptrend is an iOS app with fifteen methods.Thu, 03 Sep 2026 00:00:00 GMTcomparisonscomparisontrendweightopen-sourcehackers-diethttps://peptrend.app/blog/injection-site-rotation/https://peptrend.app/blog/injection-site-rotation/Rotation works when the order is decided in advance. Peptrend saves a site with every dose and suggests the next by round-robin through your list — no body map.Tue, 01 Sep 2026 00:00:00 GMTdose-loggingdose-logginginjectionsinjection-sitesrotationhttps://peptrend.app/blog/hull-moving-average-on-the-scale/https://peptrend.app/blog/hull-moving-average-on-the-scale/Alan Hull's filter subtracts its own lag until the line leads the scale rather than trailing it. On 84 real weigh-ins it ignores 14.3% of daily movement.Sun, 30 Aug 2026 00:00:00 GMTquanthmahull-moving-averagelagsmoothingwmahttps://peptrend.app/blog/peptrend-vs-happy-scale/https://peptrend.app/blog/peptrend-vs-happy-scale/Happy Scale does not advertise injection or dose logging and does not publish the formula behind its recommended default. Peptrend publishes fifteen and logs doses.Fri, 28 Aug 2026 00:00:00 GMTcomparisonscomparisonhappy-scalesmoothingdose-logginghttps://peptrend.app/blog/interpolation-changes-the-line/https://peptrend.app/blog/interpolation-changes-the-line/On a day you did not weigh, the app draws a straight line between your two nearest readings and hands it to the filter — 142 of 226 days on one user's log.Wed, 26 Aug 2026 00:00:00 GMTtrend-methodsinterpolationmissing-dataewmasmoothinghttps://peptrend.app/blog/kaufman-efficiency-ratio-fat-loss/https://peptrend.app/blog/kaufman-efficiency-ratio-fat-loss/KAMA squares its smoothing constant, capping the alpha near 0.048. On 84 real weigh-ins it ignores 81.3% of daily movement and ends 4.0 lb above the last weigh-in.Mon, 24 Aug 2026 00:00:00 GMTquantkamaefficiency-ratioadaptivequantsmoothinghttps://peptrend.app/blog/titration-and-how-to-chart-it/https://peptrend.app/blog/titration-and-how-to-chart-it/Peptrend colours each segment of the weight line by the dose behind it, so a 1.2 to 3.5 mg ladder reads as a four-colour ramp. Why a step takes weeks to land.Sat, 22 Aug 2026 00:00:00 GMTdose-loggingtitrationdose-loggingdose-colorschartshttps://peptrend.app/blog/kalman-filter-on-a-bathroom-scale/https://peptrend.app/blog/kalman-filter-on-a-bathroom-scale/The Kalman method carries your rate of change as part of its state and updates it with every weigh-in, so the weekly figure moves daily. Measured on 84 weigh-ins.Thu, 20 Aug 2026 00:00:00 GMTtrend-methodskalmantrend-methodsstate-spacesmoothingvelocityhttps://peptrend.app/blog/reconstitution-math-mg-ml/https://peptrend.app/blog/reconstitution-math-mg-ml/There is no single right amount — the water you add sets the strength. A 6 mg vial with 3.0 mL is 2.00 mg/mL; the same vial with 0.7 mL is 8.57 mg/mL.Tue, 18 Aug 2026 00:00:00 GMTreconstitutionreconstitutionmg-per-mlvialsconcentrationhttps://peptrend.app/blog/dema-tema-lag-reduction/https://peptrend.app/blog/dema-tema-lag-reduction/An EWMA at α = 0.1 needs 28 days to absorb 95% of a real change. DEMA gets there in 8 days and TEMA in 5 by subtracting an estimated lag, and both overshoot.Sun, 16 Aug 2026 00:00:00 GMTquantdematemalagewmasmoothinghttps://peptrend.app/blog/sma-versus-ewma-lag/https://peptrend.app/blog/sma-versus-ewma-lag/A trend line lags because it averages weigh-ins you already took. At the shipped defaults a 7-day SMA sits 3 days back and an EWMA at alpha 0.10 sits 9 days back.Fri, 14 Aug 2026 00:00:00 GMTtrend-methodssmaewmasmoothinglagtrend-methodshttps://peptrend.app/blog/glp1-half-life-and-steady-state/https://peptrend.app/blog/glp1-half-life-and-steady-state/Four to five half-lives — 28–35 days for semaglutide, 24–30 for retatrutide, 20–25 for tirzepatide. Why weekly doses stack, and what 'in your system' counts.Wed, 12 Aug 2026 00:00:00 GMTdose-logginghalf-lifepharmacokineticsdose-logginghttps://peptrend.app/blog/hackers-diet-filter-35-years-on/https://peptrend.app/blog/hackers-diet-filter-35-years-on/A trend line that skips the days you missed takes fewer steps down, so it sits above your weight: 186.0 lb against a last reading of 183.0 on one user's log.Mon, 10 Aug 2026 00:00:00 GMTtrend-methodshackers-dietewmasmoothinginterpolationhttps://peptrend.app/blog/bodyweight-is-a-time-series/https://peptrend.app/blog/bodyweight-is-a-time-series/The price-only ones, yes. DEMA, TEMA, HMA and KAMA read one number per period, so nothing in them assumes a market. On one real log they finish 4.0 lb apart.Sat, 08 Aug 2026 00:00:00 GMTquantquanttime-seriesdematemahmakamahttps://peptrend.app/blog/ewma-explained-for-weigh-ins/https://peptrend.app/blog/ewma-explained-for-weigh-ins/Your trend line travels a tenth of the way toward each new weigh-in, so a 5.4 lb morning shifts it 0.54 lb. What alpha does, and why a shock halves in 6.6 days.Sat, 08 Aug 2026 00:00:00 GMTtrend-methodsewmasmoothingalphatrend-methodshttps://peptrend.app/blog/what-to-log-with-every-dose/https://peptrend.app/blog/what-to-log-with-every-dose/Nine typed fields: time, medication, milligrams, route, site, vial, taken, pain and colour. What each one lets you answer later, and why there is no notes box.Sat, 08 Aug 2026 00:00:00 GMTdose-loggingdose-logginginjectionsglp-1record-keepinghttps://peptrend.app/blog/why-your-weight-jumps-overnight/https://peptrend.app/blog/why-your-weight-jumps-overnight/An overnight gain is water, glycogen, gut contents and sodium. In one 84-weigh-in log the daily swing ran 11.9 times the real rate of change underneath it.Sat, 08 Aug 2026 00:00:00 GMTgetting-startedwater-weightnoisesmoothinggetting-started