diff --git a/NAMESPACE b/NAMESPACE
index e9706cb88..d5e8f2778 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -99,7 +99,6 @@ export(stan_vb_opts)
 export(summarise_key_measures)
 export(summarise_results)
 export(trunc_opts)
-export(tune_inv_gamma)
 export(update_horizon)
 export(update_list)
 export(update_secondary_args)
diff --git a/R/dist.R b/R/dist.R
index 1f33bc0db..2611d7028 100644
--- a/R/dist.R
+++ b/R/dist.R
@@ -796,39 +796,6 @@ sample_approx_dist <- function(cases = NULL,
   return(mapped_cases)
 }
 
-#' Tune an Inverse Gamma to Achieve the Target Truncation
-#'
-#' @description `r lifecycle::badge("deprecated")`
-#' Allows an inverse gamma distribution to be. tuned so that less than 0.01 of
-#' its probability mass function falls outside of the specified bounds. This is
-#' required when using an inverse gamma prior, for example for a Gaussian
-#' process. As no inverse gamma priors are currently in use and this function
-#' has some stability issues it has been deprecated.
-#'
-#' @param lower Numeric, defaults to 2. Lower truncation bound.
-#'
-#' @param upper Numeric, defaults to 21. Upper truncation bound.
-#'
-#' @return A list of alpha and beta values that describe a inverse gamma
-#' distribution that achieves the target truncation.
-#' @export
-#'
-#' @keywords internal
-#'
-tune_inv_gamma <- function(lower = 2, upper = 21) {
-  lifecycle::deprecate_stop(
-    "1.3.6", "tune_inv_gamma()",
-    details = paste0(
-      "As no inverse gamma priors are currently in use and this function has ",
-      "some stability issues it has been deprecated. Please let the package ",
-      "authors know if deprecating this function has caused any issues. ",
-      "For the last active version of the function see the one contained ",
-      "in version 1.3.5 at ",
-      "https://github.com/epiforecasts/EpiNow2/blob/bad836ebd650ace73ad1ead887fd0eae98c52dd6/R/dist.R#L739" # nolint
-    )
-  )
-}
-
 #' Specify a distribution.
 #'
 #' @description `r lifecycle::badge("stable")`
diff --git a/man/tune_inv_gamma.Rd b/man/tune_inv_gamma.Rd
deleted file mode 100644
index c1c907d99..000000000
--- a/man/tune_inv_gamma.Rd
+++ /dev/null
@@ -1,26 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/dist.R
-\name{tune_inv_gamma}
-\alias{tune_inv_gamma}
-\title{Tune an Inverse Gamma to Achieve the Target Truncation}
-\usage{
-tune_inv_gamma(lower = 2, upper = 21)
-}
-\arguments{
-\item{lower}{Numeric, defaults to 2. Lower truncation bound.}
-
-\item{upper}{Numeric, defaults to 21. Upper truncation bound.}
-}
-\value{
-A list of alpha and beta values that describe a inverse gamma
-distribution that achieves the target truncation.
-}
-\description{
-\ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}}
-Allows an inverse gamma distribution to be. tuned so that less than 0.01 of
-its probability mass function falls outside of the specified bounds. This is
-required when using an inverse gamma prior, for example for a Gaussian
-process. As no inverse gamma priors are currently in use and this function
-has some stability issues it has been deprecated.
-}
-\keyword{internal}